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101.
A higher yield of Coxsackie B(1) virus was obtained when HeLa cells were infected late during S phase as compared to the amount produced by random cultures. 相似文献
102.
103.
104.
Dana J Sowa Monica M Warner Andriana Tetenych Lucas Koechlin Pardis Balari Jose
Pablo Rascon
Perez Cody Caba Sara N Andres 《Nucleic acids research》2022,50(19):11040
Bacterial non-homologous end joining requires the ligase, LigD and Ku. Ku finds the break site, recruits LigD, and then assists LigD to seal the phosphodiester backbone. Bacterial Ku contains a core domain conserved with eukaryotes but has a unique C-terminus that can be divided into a minimal C-terminal region that is conserved and an extended C-terminal region that varies in sequence and length between species. Here, we examine the role of Mycobacterium tuberculosis Ku C-terminal variants, where we removed either the extended or entire C-terminus to investigate the effects on Ku–DNA binding, rates of Ku-stimulated ligation, and binding affinity of a direct Ku–LigD interaction. We find that the extended C-terminus limits DNA binding and identify key amino acids that contribute to this effect through alanine-scanning mutagenesis. The minimal C-terminus is sufficient to stimulate ligation of double-stranded DNA, but the Ku core domain also contributes to stimulating ligation. We further show that wildtype Ku and the Ku core domain alone directly bind both ligase and polymerase domains of LigD. Our results suggest that Ku-stimulated ligation involves direct interactions between the Ku core domain and the LigD ligase domain, in addition to the extended Ku C-terminus and the LigD polymerase domain. 相似文献
105.
Acharya Balkrishna Sudeep Verma Vallabh Prakash Mulay Ashish Kumar Gupta Swati Haldar Anurag Varshney 《PLoS neglected tropical diseases》2022,16(6)
Chronic topical cases of Sporotrichosis, a chronic fungal infection caused by the ubiquitously present cryptic members of the Sporothrix species complex, are treated with oral administrations of itraconazole. However, severe pulmonary or disseminated cases require repeated intra-venous doses of amphotericin B or even surgical debridement of the infected tissue. The unavoidable adverse side-effects of the current treatments, besides the growing drug resistance among Sporothrix genus, demands exploration of alternative therapeutic options. Medicinal herbs, due to their multi-targeting capacity, are gaining popularity amidst the rising antimicrobial recalcitrance. Withania somnifera is a well-known medicinal herb with reported antifungal activities against several pathogenic fungal genera. In this study, the antifungal effect of the whole plant extract of W. somnifera (WSWE) has been explored for the first time, against an itraconazole resistant strain of S. globosa. WSWE treatment inhibited S. globosa yeast form growth in a dose-dependent manner, with IC50 of 1.40 mg/ml. Minimum fungicidal concentration (MFC) was found to be 50 mg/ml. Sorbitol protection and ergosterol binding assays, revealed that anti-sporotrichotic effects of WSWE correlated well with the destabilization of the fungal cell wall and cell membrane. This observation was validated through dose-dependent decrease in overall ergosterol contents in WSWE-treated S. globosa cells. Compositional analysis of WSWE through high performance liquid chromatography (HPLC) exhibited the presence of several anti-microbial phytochemicals like withanone, withaferin A, withanolides A and B, and withanoside IV and V. Withanone and withaferin A, purified from WSWE, were 10–20 folds more potent against S. globosa than WSWE, thus, suggesting to be the major phytocompounds responsible for the observed anti-sporotrichotic activity. In conclusion, this study has demonstrated the anti-sporotrichotic property of the whole plant extract of W. somnifera against S. globosa that could be further explored for the development of a natural antifungal agent against chronic Sporotrichosis. 相似文献
106.
The growth of bacteriophage MB78, a virulent phage of Salmonella typhimurium is extremely sensitive to the chelating agent EDTA. Other chelating agents like EGTA, a specific chelator for Ca2+ and orthophenanthroline which chelates Zn2+ and Fe2+ have no effect. EDTA stops phage MB78 DNA synthesis while synthesis of host DNA and other Salmonella phage DNA are not affected in presence of such low concentrations of EDTA. The present report indicates that some early phage function(s) and most probably the phage DNA synthesis are sensitive to EDTA which is probably due to chelation of Mg2+. 相似文献
107.
Molecular cloning of enantioselective ester hydrolase from Bacillus pumilus DBRL-191 总被引:1,自引:0,他引:1
Rasool S Johri S Riyaz-ul-Hassan S Maqbool QU Verma V Koul S Taneja SC Qazi GN 《FEMS microbiology letters》2005,249(1):113-120
A gene from Bacillus pumilus expressed under its native promoter was cloned in Escherichia coli. Recombinant B. pumilus esterase (BPE) affects the kinetic resolution of racemic mixtures such as unsubstituted and substituted 1-(phenyl)ethanols (E approximately 33-103), ethyl 3-hydroxy-3-phenylpropanoate (E approximately 45-71), trans-4-fluorophenyl-3-hydroxymethyl-N-methylpiperidine (E approximately 10-13) and ethyl 2-hydroxy-4-phenylbutyrate (E approximately 7). The enzyme is composed of a 34-amino acid signal peptide and a 181-amino acid mature protein corresponding to a molecular weight of approximately 19.2kD and pI approximately 9.4. 3-D the structural model of the enzyme built by homology modelling using the atomic coordinates from the crystal structure of B. subtilis lipase (LipA) showed a compact minimal alpha/beta hydrolase fold. 相似文献
108.
Neural cancers display cellular hierarchies with self-renewing tumorigenic cancer stem cells (CSCs) at the apex. Instructive cues to maintain CSCs are generated by both intrinsic networks and the niche microenvironment. The CSC-microenvironment relationship is complex, as CSCs can modify their environment and extrinsic forces induce plasticity in the cellular hierarchy. 相似文献
109.
The current treatment strategies, chemotherapy and radiation therapy being used for the management of cancer are deficient
in targeted approach leading to treatment related toxicities and relapse. Contrarily, fusion toxins exhibit remarkable tumor
specificity thus emerging as an alternative therapy for the treatment of cancer. Diphtheria toxin-HN-1 peptide (DT/HN-1) is
a fusion toxin designed to target the head and neck squamous cell carcinoma (HNSCC). The aim of this study was to construct,
characterize, and evaluate the cytotoxicity and specificity of DT/HN-1 fusion toxin against the HNSCC cells. The purified
DT/HN-1 fusion toxin was characterized by SDS-PAGE and western blotting. Refolding of purified fusion toxins was monitored
by fluorescence spectra and circular dichroism spectra. The activity of DT/HN-1 fusion toxin was demonstrated on various HNSCC
cell lines by cell viability assay, cell proliferation assay, protein synthesis inhibition assay, apoptosis and cell cycle
analysis. The fusion toxin DT/HN-1 demonstrated remarkably high degree of cytotoxicity specific to the HNSCC cells. The IC50 of DT/HN-1 fusion toxin was ~1 to 5 nM in all the three HNSCC cell lines. The percentage apoptotic cells in DT/HN-1 treated
UMB-SCC-745 cells are 16% compared to 4% in untreated. To further demonstrate the specific toxicity of DT/HN-1 fusion toxin
towards the HNSCC cells we constructed, characterized and evaluated the efficacy of DT protein. The DT protein coding for
only a fragment of diphtheria toxin without its native receptor binding domain failed to exhibit any cytotoxicity on all the
cell lines used in this study thus establishing the importance of a ligand in achieving targeted toxicity. To evaluate the
translocation ability of HN-1 peptide, an additional construct DTΔT/HN-1 was constructed, characterized and evaluated for
its cytotoxic activity. The fusion toxin DTΔT/HN-1 deficient of the translocation domain of diphtheria toxin showed no cytotoxicity
on all the cell lines clearly indicating the inability of HN-1 peptide to translocate catalytic domain of the toxin into the
cytosol. 相似文献
110.